1. Field of the Invention
The present invention relates to a digital broadcasting system.
2. Description of the Related Art
Since the development of digital satellite broadcasting in recent years, there has been a great increase in the number of programs being provided on an ever greater number of channels. For digital satellite broadcasting, large numbers of channels are possible by multiplexing the channels together into a single frequency band. This multiplexing is performed using what is called a xe2x80x9ctransport_streamxe2x80x9d under MPEG2 (Moving Pictures Experts Group2) standard. This technique is described in detail in the documentation for IS/IEC Standard 13818-1 (MPEG2 system standard).
Digital satellite broadcasting has a drawback in that image information is transmitted one-directionally from a transmitter, so that no interaction between the receiver and the transmitter is possible. However, users would be able to enjoy a greater variety of programs if they were able to make interactive selections of image information in accordance with the content of the image information received by the receiver terminal.
It is a primary object of the present invention to provide a digital broadcasting apparatus that one-directionally broadcasts a broadcast wave which, when received by a reception apparatus, gives the user the impression of interaction that is achieved through bidirectional communication. Here, it is the object of the present invention to further provide a reception apparatus, a digital broadcasting system, and a recording medium for recording a program to be used by a reception apparatus.
The above object can be achieved by a broadcasting apparatus for broadcasting an interactive program composed of a plurality of contents that are linked to one another, the broadcasting apparatus including: a content storing unit for storing the plurality of contents, each content including a set of video data and a set of control information that indicates another content that is a link destination for a present content, and a transmitting unit for multiplexing a set of video data and a plurality of sets of the same control information included in a same content as the set of video data, and for transmitting the multiplexed sets of video data and control information.
Here, the content storing unit may include: a first storing unit for storing the sets of video data included in the plurality of contents; a second storing unit for storing the sets of control information included in the plurality of contents; and a construction table storing unit for storing a construction table showing correspondence between the sets of video data stored in the first storing unit and the sets of control information stored in the second storing unit.
Here, the transmitting unit may include: a multiplexing unit for reading the plurality of sets of video data stored in the first storing unit and the plurality of sets of control information stored in the second storing unit as respective digital data streams, and multiplexing the digital data streams to generate a multiplexed stream; a multiplexing control unit for referring to the construction table and controlling the multiplexing unit to multiplex the plurality of sets of video data and to repeatedly multiplex a set of control information corresponding to a set of video data; and a broadcasting unit for placing the multiplexed stream generated by the multiplexing unit onto a digital broadcast wave and broadcasting the digital broadcast wave.
Here, the content storing unit may further include: a third storing unit for storing sets of audio data that correspond to the sets of video data, wherein the construction table storing unit stores correspondence between a set of video data, a set of audio data, and a set of control information included in each of the plurality of contents, and wherein the multiplexing unit also multiplexes the sets of audio data stored in the third storing unit into the multiplexed stream.
With the above construction, control information is repeatedly multiplexed with the video data and is transmitted, so that the reception apparatus can perform reproduction while interactively switching between contents in accordance with user operations. This is to say, the present digital broadcasting apparatus can provide interactive programs using a one-directional broadcast.
Here, each content may include a plurality of sets of control information, each set of control information including a set of link information showing contents that are link destinations and a set of time information indicating a valid period for the present control information within the reproduction period of the set of video data corresponding to the present set of control information, and the multiplexing control unit may control the multiplexing unit to repeatedly multiplex each set of control information with the corresponding set of video data during the valid period of the set of control information.
With the stated construction, the digital broadcasting apparatus can repeatedly and freely multiplex different sets of control information for different periods within the reproduction time of sets of video data, so that the link destination contents and number of potential links can be dynamically changed in accordance with the content of the video data. As a result, each content can be linked to appropriate link destination contents for the content of each scene in the video data.
Here, the multiplexing control unit may control the multiplexing unit to repeatedly multiplex each set of control information with the corresponding video data starting from a predetermined time before the valid period of the set of control information, the predetermined time being sufficiently long to enable a reception apparatus to process a set of control information.
With the stated construction, control information is repeatedly multiplexed with the video data starting from a predetermined time before the valid period of the control information, so that when a content is being reproduced by the reception apparatus, the reception apparatus will have enough time to process new control information which has a different valid period.
Here, the multiplexing control unit may append a version number, reflecting the valid period of each set of control information, to each set of control information in a given content.
With the stated construction, the reception apparatus can obtain new control information with a different valid period for a same content using the version numbers.
Here, each set of control information stored by the second storing unit may include a set of link information showing contents that are link destinations and supplementary images representing menu items for each link destination.
With the stated construction, menu items for assisting user operations in the reception apparatus can be freely set in each set of control information.
Here, at least one set of control information may include: a plurality of sets of additional information representing one of text and a graphic image that is to be displayed superimposed onto the corresponding video data; and a set of script information that validates one of the sets of additional information within a reception apparatus, in accordance with a user operation.
With the stated construction, sets of control information can be provided with script information and a plurality of sets of additional information, with the reception apparatus being able to interactively switch between the sets of additional information. As one example, when the video data expresses a weather forecast and the sets of additional information provide a plurality of supplementary explanations (text or graphics) relating to the content of the video data, switching of the display of supplementary explanations can be performed using the script information in accordance with the user operations. By doing so, one pair of a set of video data and a set of control information can be used to express what are effectively a plurality of contents.
Here, at least one set of control information may include: at least two groups of a set of link information and supplementary images; a set of initial information showing a group of a set of link information and supplementary images that is valid at a start of reproduction by a reception apparatus for a content including the present set of control information; and a set of script information that changes a valid setting in the reception apparatus in accordance with a user operation.
With the stated construction, sets of control information are provided with a plurality of groups which may be switched according to the script information, so that an effective increase in the number of link destination contents can be achieved.
Here, each group of a set of link information and supplementary image may further include a set of additional information representing one of text and a graphic image that is to be displayed superimposed onto the corresponding video data.
With the stated construction, the groups are provided with additional information, so that one pair of a set of video data and a set of control information can be used to effectively express a plurality of contents that have different link destination contents according to the additional information.
The object of the present invention can also be achieved by a broadcasting apparatus for broadcasting an interactive program composed of a plurality of contents that are linked to one another, the broadcasting apparatus including an image storing unit storing a plurality of sets of video data and a plurality of sets of still image data; a control information storing unit for storing sets of type 1 control information and sets of type 2 control information, the sets of type 1 control information being elements of contents including video images, the sets of type 2 control information being elements of contents including still images, and the sets of type 1 control information and sets of type 2 control information including sets of link information that indicate contents which are link destinations for a present content; a construction table storing unit storing a first construction table showing correspondence between sets of video data and sets of type 1 control information and a second construction table showing correspondence between sets of still image data and sets of type 2 control information; a first multiplexing unit for generating a first multiplexed stream by multiplexing a set of video data in the first construction table and repeatedly multiplexing a set of type 1 control information corresponding to the set of video data; a second multiplexing unit for generating a second multiplexed stream by repeatedly multiplexing a plurality of sets of still image data in the second construction table with a set of type 2 control information; and a broadcasting unit for placing the multiplexed stream generated by the multiplexing unit onto a digital broadcast wave and broadcasting the digital broadcast wave.
With the stated construction, interactive programs that are made up of two types of contents, which is to say video-based contents and still-based contents, can be broadcasted. Type 1 and type 2 control information can have both kinds of contents as link destination contents, so that a reception apparatus can perform reproduction switching between both kinds of content in accordance with user operations. In this way, very impressive interactive programs can be realized.
The above object can also be achieved by a reception apparatus for receiving a broadcast wave including an interactive program composed of a plurality of contents that are linked to one another, wherein the broadcast wave includes a multiplexed stream into which different sets of video data have been multiplexed with a plurality of sets of control information showing a link to another content, the sets of control information being repeatedly multiplexed, the reception apparatus including: an extracting unit for extracting a set of video data and a set of control information in a same content as the set of video data; a storing unit for storing the extracted set of control information; a reproducing unit for reproducing the extracted set of video data and outputting an image signal; an operation unit for receiving a user operation that indicates a content switching; and a control unit for controlling the extracting unit to extract another content indicated by the set of control information stored in the storing unit, in accordance with the user operation.
With the stated construction, the reception apparatus can behave interactively as if two-way communication were being performed, despite only using a one-directional broadcast of image information, meaning that users can enjoy interactive programs. Since the control information is repeatedly transmitted, the storing unit only requires enough storage capacity to store the control information for one content.
Here, first identification information may be appended to each set of video data and second identification information is appended to each set of control information, and wherein the sets of control information include first identification information and second identification information which express a content of a link destination, the extracting unit may include: a first judging unit for judging the first identification information appended to sets of video data in the broadcast wave; a second judging unit for judging the second identification information appended to sets of control information in the broadcast wave; an obtaining unit for obtaining a set of video data and when the first judging unit judges that the first identification information coincides with specified identification information indicated by the control unit and obtaining a set of control information when the second judging unit judges that the second identification information coincides with specified identification information, the reproducing unit may reproduce the set of video data obtained by the obtaining unit, and the storing unit may store the set of control information obtained by the obtaining unit.
With the stated construction, the reception apparatus judges the sets of video information and control information and obtains the appropriate data, so that the only the data to be reproduced is obtained, thereby improving the reception efficiency.
Here, a set of entry information giving first identification information and second identification information for the content to be reproduced first may be multiplexed into the multiplexed stream, the control unit may send an indication to the extracting unit to extract the set of entry information when the operation unit has received a selection operation for a multiplexed stream from a user, the extracting unit may further include: an entry information extracting unit for receiving the indication from the control unit and extracting the set of entry information from the multiplexed stream; and an entry information storing unit for storing the set of entry information extracted by the entry information extracting unit, wherein the control unit may give the obtaining unit an indication of the first identification information and second identification information included in the entry information as the specified identification information.
With the stated construction, the reception apparatus can extract the content to be reproduced first in accordance with the entry information, so that contents which contain important information, such as a main menu, can definitely be reproduced.
Here, the link information may include an identifier of a set of video data and an identifier of a set of control information which show a content of a link destination, the first identification information and second identification information may be IDs (identifiers) of digital data streams which represent a set of video data and a set of control information in the multiplexed stream, a correspondence table, showing correspondence between the identifiers for sets of video data and the first identification information and correspondence between the identifiers for sets of control information and the second identification information, may be multiplexed into the multiplexed stream and repeatedly transmitted, and the extracting unit may extract the correspondence table and the control unit may refer to the correspondence table, convert an identifier of the set of video data included in the link information into first identification information and an identifier of the set of control information into second identification information and inform the extracting unit of the converted first and second identification information.
With the stated construction, the interactive programs of the present invention are broadcast using a digital satellite broadcast according to MPEG2 standard, so that the present invention can be achieved by modifying a conventional digital satellite broadcast tuner.
Here, at least one set of control information may include link information showing a content of a link destination and supplementary images that include a menu item image for each link destination, the reproducing unit may include: a video data reproducing unit for reproducing the set of video data obtained by the obtaining unit; and an image reproducing unit for reproducing supplementary images stored by the storing unit superimposed onto the video data, wherein the operation unit may receive a user selection of a menu item image, and wherein the control unit may determine the first identification information and the second identification information of a link destination content in accordance with the link information and the menu item image selected by the user.
With the stated construction, menu item images are displayed by the reception apparatus, assisting the interactive operations of the user and enabling the achievement of impressive interactive programs.
Here, at least one set of control information may include additional information which expresses one of a text image and a graphics image, and wherein the reproducing unit may additionally reproduce one of the text image and graphics image stored in the storing unit superimposed onto the video data.
With the stated construction, additional images such as text or graphics are displayed in addition to the video data, making the interactive programs even more impressive.
Here, each set of control information may include valid period information showing a valid period of the set of control information, wherein each content may have a plurality of sets of control information which have different valid periods, and wherein the reproducing unit may reproduce supplementary images stored in the storing unit only during a valid period of the set of control information stored in the storing unit.
With the stated construction, sets of control information with different valid periods within the reproduction time of video data are repeatedly multiplexed, so that the link destination contents and number of potential links can be dynamically changed in accordance with the content of the video data. As a result, each content can be linked to appropriate link destination contents for the content of each scene in the video data. As a result, the user of the reception apparatus can gain greater enjoyment from the interactive programs which have link destinations that correspond to the video scenes.
Here, each of the plurality of sets of control information for a same content has a version number that reflects the valid period, and wherein the control unit controls the extracting unit to extract a set of control information which has a next version number, when one set of control information has been extracted by the extracting unit.
With the above construction, the reception apparatus can use the version numbers for the content presently being reproduced and so obtain following sets of control information with different valid periods.
Here, at least one set of control information may include a plurality of sets of additional information which each express one of a text image and a graphics image to be displayed superimposed onto the video data, and a set of script information that validates one of the sets of additional information within a reception apparatus, in accordance with a user operation, wherein the control unit may determine a valid set of additional information by interpreting and executing the script information stored in the storing unit, and wherein the reproducing unit may reproduce one of the text image and the graphics image included in the valid set of additional information based on a result of interpreting and executing by the control unit.
With the stated construction, the reception apparatus does not need to obtain new control information, and so can perform content switching in accordance with the script information. Such content switching performed entirely by the execution of script information is much more responsive to user operations.
Here, the multiplexed stream may include sets of audio data corresponding to the sets of video data, wherein the extracting unit may extract a set of audio data corresponding to a set of video data from the broadcast wave, and wherein the reproducing unit may additionally reproduce the extracted set of audio data.
With the stated construction, interactive programs composed of contents including video, stills, and audio can be realized.
The stated object can also be achieved by a recording medium used by a reception apparatus that includes a receiving unit for receiving a broadcast wave including an interactive program composed of a plurality of contents that are linked to one another, an extracting unit for extracting one digital data stream from the broadcast wave, and a reproducing unit for reproducing a set of video data and outputting an image signal, the recording medium storing a program that includes the following steps: an extracting step for extracting a set of video data and a set of control information in a same content as the set of video data from the broadcast wave; a storing step for storing the extracted set of control information into a memory in the reception apparatus; a reproducing step for reproducing the extracted set of video data and outputting an image signal; a judging step for judging whether a user operation indicating a switching of content has been made; and a control step for controlling the extracting unit to extract another content indicated by the set of control information stored in the memory, when the judging step judges that a user operation indicating a switching of content has been made.
With the stated recording medium, the program can be installed into a conventional reception apparatus (satellite broadcast tuner), so that the present invention can be easily realized.